<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css">
		.box {
			width: 577px;
			height: 100px;
			background-color: pink;
			display: flex;
		}

		.box>div {
			background-color: yellowgreen;
		}

		div.one {
			flex: 1;
			background-color: red;
		}

		div.two {
			flex: 2;
			background-color: blue;
		}
		
		div.three {
			flex: 1;
		}

	</style>
</head>
<body>
	
	<div class="box">
		<div class="one"></div>
		<div class="two"></div>
		<div class="three"></div>
	</div>
</body>
</html>